System for distributed verification of satellite position

Abstract

A satellite for implementing a protocol associated with a distributed satellite position verification system is provided. The satellite, on implementing the protocol, verifies records of positions of one or more other satellites in the distributed satellite position verification system. According to the protocol, the satellite performs, at different time instances, a first operation, a second operation, or a third operation to act as a first satellite, a second satellite, or a third satellite, respectively in the distributed satellite position verification system. When the first satellites performs the first operation, the first satellite verifies at least some positions in the records of positions of the second satellite such that the first satellite: determines a verified position of the second satellite; calculates a deviation between the verified position and a prior estimated position of the second satellite; and records the verified position into the records, based on the calculated deviation.

The invention claimed is: 
     
       1. A satellite configured to implement a protocol associated with a distributed satellite position verification system, the satellite comprising:
 a positioning system configured to estimate a current position of the satellite at a current instance of time; 
 a transceiver configured to participate in a telemetric exchange with one or more other satellites; and 
 a processor coupled with stored instructions implementing the protocol, the stored instructions when executed by the processor cause the satellite to:
 generate a report recording the estimated current position of the satellite; 
 verify records of positions of the one or more other satellites in the distributed satellite position verification system including a first satellite, a second satellite, and a third satellite, wherein: the first satellite is configured to perform a first operation, the second satellite is configured to perform a second operation, the third satellite is configured to perform a third operation, wherein according to the protocol, the satellite is configured to perform, at different time instances, the first operation, the second operation, or the third operation to act as the first satellite, the second satellite, or the third satellite respectively, and wherein according to the protocol, the first satellite is configured to verify at least some positions in the records of positions of the second satellite by performing the first operation, such that the first satellite is configured to:
 determine a verified position of the second satellite by participating in the telemetric exchange with the second satellite and the third satellite; 
 calculate a deviation between the verified position of the second satellite and a prior estimated position of the second satellite; and 
 record the verified position into the records of positions of the second satellite, based on the calculated deviation. 
 
 
 
     
     
       2. The satellite of  claim 1 , wherein to participate in the telemetric exchange, the first satellite is further configured to exchange a plurality of radio signal with each of the second satellite and the third satellite in a predefined order. 
     
     
       3. The satellite of  claim 2 , wherein to determine the verified position of the second satellite, the first satellite is further configured to:
 determine a position of the second satellite at a particular time instance, based on at least one physical property of the radio signals; 
 determine a confidence value associated with the determined position of the second satellite at the particular time instance; and 
 determine the verified position of the second satellite, based on the confidence value. 
 
     
     
       4. The satellite of  claim 3 , wherein to determine the verified position of the second satellite, the first satellite is further configured to:
 compare the confidence value with a predefined confidence value bound; 
 determine the verified position of the second satellite as a self-reported verified position, when the confidence value is not greater than the predefined confidence bound; and 
 determine the verified position of the second satellite as a self-reported unverifiable position, when the confidence value is greater than the predefined confidence bound. 
 
     
     
       5. The satellite of  claim 3 , wherein to determine the position of the second satellite at the particular time instance, the first satellite is further configured to identify at least one observer satellite for determining the position of the second satellite. 
     
     
       6. The satellite of  claim 1 , wherein the calculated deviation is a Euclidean distance between the verified position of the second satellite and the prior estimated position of the second satellite. 
     
     
       7. The satellite of  claim 1 , wherein to record the verified position of the second satellite into the records of positions of the second satellite, the first satellite is further configured to:
 compare the calculated deviation with a predefined deviation bound; and 
 record the verified position into the records of positions of the second satellite, when the calculated deviation is not greater than the predefined deviation bound. 
 
     
     
       8. The satellite of  claim 1 , wherein the protocol further comprises operations to withdraw a privilege associated with the second satellite, based on at least one of a trust violation score, a confidence violation score, and a participation violation score. 
     
     
       9. The satellite of  claim 8 , wherein to withdraw the privilege associated with the second satellite, the protocol further comprises the operations to:
 calculate the trust violation score for the second satellite within a window of a predefined length of verified positions associated with the second satellite; 
 compare the calculated trust violation score with a predefined trust violation score bound; and 
 withdraw the privilege associated with the second satellite, when the calculated trust violation score is greater than the predefined trust violation score bound. 
 
     
     
       10. The satellite of  claim 8 , wherein to withdraw the privilege associated with the second satellite, the protocol further comprises the operations to:
 calculate the confidence violation score for the second satellite within a window of a predefined length of verified positions associated with the second satellite; 
 compare the calculated confidence violation score with a predefined confidence violation score bound; and 
 withdraw the privilege associated with the second satellite, when the calculated confidence violation score is greater than the predefined confidence violation score bound. 
 
     
     
       11. The satellite of  claim 8 , wherein to withdraw the privilege associated with the second satellite, the protocol further comprises the operations to:
 calculate the participation violation score for the second satellite within a window of a predefined length of verified positions associated with the second satellite; 
 compare the calculated participation violation score with a predefined participation violation score bound; and 
 withdraw the privilege associated with the second satellite, when the calculated participation violation score is greater than the predefined participation violation score bound. 
 
     
     
       12. The satellite of  claim 1 , wherein to record the verified position into the records of positions of the second satellite, the first satellite is further configured to log the verified position into the records of positions of the second satellite as a block chain transaction. 
     
     
       13. The satellite of  claim 1 , wherein the first satellite and the third satellite are within a line of sight (LOS) of the second satellite. 
     
     
       14. The satellite of  claim 1 , wherein the satellite, at one time instance of the different time instances, is configured to act as the first satellite, the second satellite, or the third satellite, based on a trust score associated with the satellite. 
     
     
       15. A method for implementing a protocol associated with a distributed satellite position verification system, comprising:
 estimating, by a positioning system, a current position of a satellite at a current instance of time; 
 participating, by a transceiver, in a telemetric exchange with one or more other satellites; 
 generating, by a processor coupled with stored instructions implementing the protocol, a report for recording the estimated current position of the satellite; 
 verifying, by the processor, records of positions of the one or more other satellites in the distributed satellite position verification system including a first satellite, a second satellite, and a third satellite, wherein: the first satellite is configured for performing a first operation, the second satellite is configured for performing a second operation, the third satellite is configured for performing a third operation, wherein according to the protocol, the satellite is configured for performing, at different time instances, the first operation, the second operation, or the third operation to act as the first satellite, the second satellite, or the third satellite respectively, and wherein according to protocol, the first satellite is configured for verifying at least some positions in the records of positions of the second satellite by performing the first operation, such that the first satellite is configured for:
 determining a verified position of the second satellite by participating in the telemetric exchange with the second satellite and the third satellite; 
 calculating a deviation between the verified position of the second satellite and a prior estimated position of the second satellite; and 
 recording the verified position into the records of positions of the second satellite, based on the calculated deviation. 
 
 
     
     
       16. A non-transitory computer readable storage medium embodied thereon a program executable by a satellite for performing a method associated with a distributed satellite position verification system, the method comprising:
 estimating, by a positioning system, a current position of the satellite at a current instance of time; 
 participating, by a transceiver, in a telemetric exchange with one or more other satellites; 
 generating, by a processor coupled with stored instructions implementing the protocol, a report for recording the estimated current position of the satellite; 
 verifying, by the processor, records of positions of the one or more other satellites in the distributed satellite position verification system including a first satellite, a second satellite, and a third satellite, wherein: the first satellite is configured for performing a first operation, the second satellite is configured for performing a second operation, the third satellite is configured for performing a third operation, wherein according to the protocol, the satellite is configured for performing, at different time instances, the first operation, the second operation, or the third operation to act as the first satellite, the second satellite, or the third satellite respectively, and wherein according to protocol, the first satellite is configured for verifying at least some positions in the records of positions of the second satellite by performing the first operation, such that the first satellite is configured for:
 determining a verified position of the second satellite by participating in the telemetric exchange with the second satellite and the third satellite; 
 calculating a deviation between the verified position of the second satellite and a prior estimated position of the second satellite; and 
 recording the verified position into the records of positions of the second satellite, based on the calculated deviation.